Linearly-arranged lens assemblies have been used in many applications to modify a beam of light. The curvature of the lens, the size of the lens, the number of lenses, distance separating lenses, and the distance between the beam of light and the lenses are all variables in modification. Lens assemblies are typically secured permanently in a lens holder composed of metal or plastic for placement in a system. Lenses are typically mechanically secured for by example a screw, sealant or elastic at a position in the lens holder.
The conventional way of accomplishing beam modification in an optical system is to affix a lens holder at a specific location within a lighting fixture. A single lens holder containing a lens or an assembly of lenses attaches within the fixture with screws or the like along the path of the optical axis.
In the entertainment lighting industry, the specification of a particular lighting fixture, in many cases, may include the beam angle. The beam angle describes the rate at which the beam emanates from the fixture as it travels from the fixture toward a target. In many prior art fixtures, the beam angle can be varied automatically by mechanical systems that move the position of one or more of the lenses in the optical path relative to the other lenses in the optical path. In many cases, these mechanisms can be operated automatically and/or remotely by control systems that are well known. However, the costs of these mechanical systems can be prohibitive for many applications. As a result in many prior art fixtures, changing the beam angle available requires tools to remove the current lens holder and install a new holder. In addition, the fixture modularity is often limited by the single position available for installing the lens holder within the fixture.
The ability to change lens systems easily and in a timely manner within a fixture would provide beam modification interchangeability to the fixture by giving the user a plurality of interchangeable lens assembly configurations for use in a single fixture. Multiple positions available for placement of lenses and lens assemblies in a fixture would provide beam modification modularity by giving the user a fixed plurality of positions for lens placement.